Capping of sensitive micromechanical components was originally carried out by bonding or gluing a cap wafer onto a completely processed sensor wafer.
In recent years a new capping method, thin-layer capping, has been developed which dispenses with a cap wafer, and instead a cavity or cavern is provided between the micromechanical structures to be exposed and a silicon layer, as the cap layer, which is produced using a customary deposition process.
A method is discussed in German patent document DE 10 2006 049 259 A1, as being for manufacturing a micromechanical component having a cap layer, a cap layer being deposited onto a filling layer, and micropores then being formed in the cap layer. The filling layer is then removed by gas phase etching, using ClF3 which is passed through the micropores, the selectivity of the etching medium mixture and the composition of the filling layer being set in such a way that the selectivity with respect to the cap layer is high enough that the cap layer is not attacked. After the filling layer is removed, the micropores are sealed by depositing a sealing layer.
German patent document DE 10 2007 022 509 A1 discusses a manufacturing method for a micromechanical component having thin-layer capping, a gas which has a nonatmospheric composition on account of the decomposition of a polymer being trapped in the cavern.